This invention relates to printing apparatuses and processes, and more particularly to automated or manual printing by silk screening. It further relates to all types of ink printing presses using squeegee mechanisms for pressing the ink through the screen.
Numerous printing apparatuses are known, including those shown in U.S. Pat. Nos. 2,975,705 and 3,955,501, the contents of which are hereby incorporated by reference in their entirety. Basically they show a support frame positionable on top of a screen frame. Means attached to the support frame deposit ink on the screen and then force it through the screen pattern onto an underlying substrate. Solvents can be sprayed on the ink to keep it at its proper consistency and thus to keep it from drying out. However, these harmful solvents and other chemicals are thereby released into the environment endangering the health of the operator and others standing nearby. Another problem associated with prior screen printing apparatus is that the ink rapidly dries on the screen and the whole process must be periodically shut down so that the screen can be cleaned.
On occasion in the past, large, cumbersome hoods which fit over the entire press have been custom designed and used. These hoods have doors through them to provide access to the squeegee/floor bar pressure adjustments, hinge clamps, and other controls. The press would have to be shut down at a certain position, however, to allow adjustment of the controls through that door. Additionally, this design created a safety hazard since solvent fumes were contained within the hood, and these fumes could be ignited by the contact of the metal press parts or from the electrical connections of the press.
The screen printing apparatus disclosed in U.S. Pat. No. 4,545,300 has certain disadvantages which the present invention remedies. For example, that apparatus will not work on all types of presses. That apparatus also presents an undesirably deep framework which does not allow the apparatus to fit into the master frame which sits around the press. It further was a time-consuming process to attach the novel chamber arrangement of that apparatus to the silk screen frame and to properly align the bearings for each use.